The thebesian veins are small venous tributaries that drain directly into the cardiac chambers.

Coronary blood flow is 225 ml/ min on the average which is _____% of the C.O.

4 to 5

Controllers of oxygen to the heart

1. Response to nutritional need
2. Oxygen demand is a major factor
3. Adenosine is the most likely vasodilator although H+, carbon dioxide, bradykinin, prostaglandins, and adenosine phosphate metabolites are the other possibilities.